Monthly new water fractions and their relationships with climate and catchment properties across Alpine rivers

• Published in: Hydrology and earth system sciences Vol. 28; no. 16; pp. 3675 - 3694
• Main Authors: Floriancic, Marius G, Stockinger, Michael P, Kirchner, James W, Stumpp, Christine
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 16.08.2024; Copernicus Publications
• Subjects: Base flow; Catchment area; Catchments; Climate; Correlation; Creeks & streams; Drinking water; Dry periods; Hydroelectric power; Isotopes; Partitioning; Precipitation; Rain; Rain and rainfall; Rainfall; Rankings; Rivers; Snow; Stream discharge; Stream flow; Streamflow; Streams; Sustainability management; Time series; Water; Water management; Water resources; Water-power; Alps; Switzerland
• ISSN: 1027-5606; 1607-7938
• DOI: 10.5194/hess-28-3675-2024

The Alps are a key water resource for central Europe, providing water for drinking, agriculture, and hydropower production. Thus, understanding runoff generation processes of Alpine streams is important for sustainable water management. It is currently unclear how much streamflow is derived from old water stored in the subsurface and how much stems from more recent precipitation that reaches the stream via near-surface quick flow processes. It is also unclear how this partitioning varies across different Alpine catchments in response to hydroclimatic forcing and catchment characteristics. Here, we use stable water isotope time series in precipitation and streamflow to quantify the young water fractions (F.sub.yw ; i.e., the fraction of water younger than approximately 2-3 months) and new water fractions (F.sub.new ; here, the fraction of water younger than 1 month) in streamflow from 32 Alpine catchments. We contrast these measures of water age between summer and winter and between wet and dry periods and then correlate them with hydroclimatic variables and physical catchment properties.